my scientific age

Chapter 32 Probability and Statistics
Lin Wan was not as straightforward as Yu Hua. She got up and went to the toilet to wash her hands. She returned to her seat. She took out a graceful handkerchief from her bag, wiped her hands, and then took out the rice spoon. The spoon scooped up the white radish. Although the meal was simple, the manners were correct and orderly.

Yu Hua glanced at the dining appearance of the boss next door, Lin Wan, and sighed in his heart that he was indeed a child raised by an upper-class family.

Keep your mouth and your hands free.

After three times and five divisions, Yu Hua ate his dinner. After filling his stomach, he quickly washed the dishes, and then went back to his seat to start busy.

English homework is relatively simple, just write an essay, and write a running account, telling the process of going out to school, even if you live together.

Party morality requires writing articles on the domestic political pattern and parties, from the political situation of the Qing Dynasty to the civil affairs situation, with a careful description.

Party righteousness, which is the politics of later generations, should be classified as liberal arts. However, due to the times and the environment, whether it is first-class literature or second-class science, it is mandatory to learn party righteousness.

Of course, the students of this era have a very high literary literacy, and there is no difficulty in saving national literature and party morality.

Regarding Party justice, Yu Hua has no unique opinion, and he doesn't need to give any opinion, just follow the rules. After two hours, at [-] o'clock in the evening, the Party justice holiday homework is completed.

"Huh, it's finally finished, it's still early, let's look at math." Yu Hua put down the pen, his right hand was sour, and he rubbed his wrist lightly. Looking at the party's righteous homework full of handwriting, he breathed a sigh of relief and felt his state. Okay, get ready to do some math for a while.

Mathematics is the main subject, which cannot be ignored.

It's 11 o'clock now, and the library will close at [-] o'clock, which is still very early.

Rubbing her wrists, Yu Hua looked up and looked around. Lin Wan was still sitting next to her, holding a pen. She didn't know what she was writing. All the desks around were filled with students in thick cotton coats, reading books with the help of the library lights. Some people wrote and answered the questions, while others read in a low voice and recited the text.

There is a rule in the school that except for studying in the library, students must turn off the lights and go to bed before 10:[-] and [-] minutes. This rather magical rule gave birth to the motivation for students to go to the library.

At night, the whole school has no other light sources except the library, not even the street lights.

Looking at the surrounding situation, there was a strong learning atmosphere in the air. Yu Hua took a short rest for 10 minutes, calmed down, and felt that his condition seemed to be back. He opened the mathematics textbook without stopping, and started a new study.

Today, I have been copying homework all day, and I don't have much time to do questions and study. The physical load and consumption are not high. Yu Hua is just feeling a little tired now, and he has not reached his usual learning limit.

In the morning, the arithmetic progress reached the trigonometric function line to solve the inequality, and Yu Hua went directly to the trigonometric function line to prove the trigonometric function inequality rule.

Prove it: when x∈(0,π/2), sinx＜x＜tanx
After reading this question, Yu Hua already had an idea in his mind. This question is based on the trigonometric function line. The test is based on the combination of the area formula of the sector and the number and shape. As long as the unit circle is drawn and the trigonometric function line is marked , and then convert the inequality required to prove it into an intuitive comparison of the size of line segments and radians, and you can solve the problem easily.

With a relaxed and calm expression, Yu Hua held a pencil in his right hand, and quickly drew a rectangular coordinate system and a unit circle on the scratch paper, and marked the trigonometric function line. After a simple observation, he knew the answer in his heart.

After 1 minute, the answer is given.

After mastering the knowledge points, moving his eyes down, and looking at the domain of trigonometric functions, Yu Hua has fully understood the domain of definition problem. The solution of the domain of trigonometric functions mainly masters the tangent function, and the domain of definition of the tangent function Y=tanx: X ≠π/2+kπ, k∈Z.

He has already used this knowledge point in the final topic of solving inequalities with trigonometric function lines.

Trigonometric function domain, too.

Use the induction formula to compare the size, too.

Trigonometric symmetry, too.

Trigonometric inequalities proof problem, too.

"Shhhhh..." The sound of the pencil swiping at a high speed continued to be heard. The speed of the swipe was so fast that Lin Wan, who was studying, heard the movement. , shook his head slightly.

At this moment, compared to the tortured state of writing Chinese, English, and party ethics, Yu Hua, who returned to mathematics, only felt refreshed and comfortable, and felt that there was nothing more comfortable in the world than learning mathematics.

Time passed slowly, and Yu Hua, who was immersed in the state of ecstasy, brushed the questions faster and faster. After about half an hour, he fully mastered the entire chapter of arithmetic trigonometry. For each difficult knowledge point, Yu Hua mastered at least three solutions, and the accumulation of knowledge was extremely solid. .

Completely mastering trigonometry means that Yu Hua's learning progress has completely kept up with the rhythm of his class. The mathematics textbook officially announced that he is approaching the end of his life, and there are still many barriers to set up. The last step is probability statistics.

Probability and statistics is the key content that will be covered in the sixth semester, and it is also the focus and difficulty of high school mathematics in later generations.

As long as the probability is crossed, so far, the mathematics textbook will be smooth, and there will be no more difficulties.

"continue!"

Looking at the traditional introduction of the probability and statistics chapter, Yu Hua took a deep breath. He was not proud. The knowledge he has now can only be described as superficial. The mathematics textbooks in the Republic of China were not very difficult. , It is enough to get the oxygen top-blown converter technology in the plan, let alone other things.

Don't be complacent, don't be complacent.

Run, run, run!
The momentum is like a tiger, and a true scholar must have his own momentum.

Opening Chapter 1 of Probability and Statistics—the definition of counting principle, Yu Hua looked at the unfamiliar but familiar mathematical description, and gradually immersed himself in the state of learning. The whole person was like a dry sponge, absorbing efficiently Mathematical knowledge of this era.

Compared with the complete and comprehensive probability and statistics of later generations, the probability and statistics of the Republic of China period lacked some content, but the basic counting principle, permutation and combination, binomial theorem, random event probability and geometric probability, and the most core normal distribution. , many kinds.

"Boom!"

At eleven o'clock in the evening, with a dull and distant bell from the school, the closing time of the library had come.

Many students withdrew from their studies and packed their things and left.

Lin Wan, who had been studying English all night, typed Hache, and packed up her books and tools. When she was finished, she glanced at Yu Hua, who was still writing at the desk next door, and patted Yu Hua on the shoulder: "Classmate, it's eleven o'clock. Now, it's closing."

"I'm sorry, it's too fascinated to watch." Feeling someone filming himself, Yu Hua suddenly withdrew from his study state, a little puzzled, and when he looked up, he saw that it was Lin Wan, and there were bursts of bells in his ears. Kindly scratched his head.

"It's the first time I can read the book of arithmetic as a literary masterpiece." Lin Wan couldn't help smiling and sighed when she saw Yu Hua's unfinished expression.

(End of this chapter)